Reland "Add pixel test for AccessibilityFocusHighlight based on FocusRingBrowserTest"

This is a reland of b89144a4

Original change's description:
> Add pixel test for AccessibilityFocusHighlight based on FocusRingBrowserTest
>
> AX-Relnotes: n/a
>
> Bug: 1114959
> Change-Id: Ib6d9f51a04fa8059dc6bd6192d182b8e0244367d
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2352451
> Commit-Queue: Alice Boxhall <aboxhall@chromium.org>
> Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
> Reviewed-by: Joey Arhar <jarhar@chromium.org>
> Reviewed-by: Mason Freed <masonfreed@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#803007}

TBR=ellyjones@chromium.org,masonfreed@chromium.org,jarhar@chromium.org

Bug: 1114959
Change-Id: I1997496df505691103568989a9cbfaa38e4e9b0e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2388025Reviewed-by: Alice Boxhall <aboxhall@chromium.org>
Commit-Queue: Alice Boxhall <aboxhall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#804034}

chrome/browser/ui/views/accessibility/accessibility_focus_highlight.cc

@@ -77,6 +77,9 @@ bool AccessibilityFocusHighlight::skip_activation_check_for_testing_ = false;
 // static
 bool AccessibilityFocusHighlight::use_default_color_for_testing_ = false;
 
+// static
+bool AccessibilityFocusHighlight::no_fade_for_testing_ = false;
+
 AccessibilityFocusHighlight::AccessibilityFocusHighlight(
     BrowserView* browser_view)
     : browser_view_(browser_view) {
@@ -98,7 +101,7 @@ AccessibilityFocusHighlight::AccessibilityFocusHighlight(
     fade_in_time_ = kFadeInTime;
     persist_time_ = kHighlightPersistTime;
     fade_out_time_ = kFadeOutTime;
-    default_color_ = SkColorSetRGB(16, 16, 16);  // #101010
+    default_color_ = SkColorSetRGB(0x10, 0x10, 0x10);  // #101010
   }
 }
 
@@ -109,9 +112,7 @@ AccessibilityFocusHighlight::~AccessibilityFocusHighlight() {
 
 // static
 void AccessibilityFocusHighlight::SetNoFadeForTesting() {
-  fade_in_time_ = base::TimeDelta();
-  persist_time_ = base::TimeDelta::FromHours(1);
-  fade_out_time_ = base::TimeDelta();
+  no_fade_for_testing_ = true;
 }
 
 // static
@@ -124,7 +125,17 @@ void AccessibilityFocusHighlight::UseDefaultColorForTesting() {
   use_default_color_for_testing_ = true;
 }
 
+// static
+ui::Layer* AccessibilityFocusHighlight::GetLayerForTesting() {
+  return layer_.get();
+}
+
 SkColor AccessibilityFocusHighlight::GetHighlightColor() {
+#if !defined(OS_MAC)
+  // Match behaviour with renderer_preferences_util::UpdateFromSystemSettings
+  // setting prefs->focus_ring_color
+  return default_color_;
+#else
   ui::NativeTheme* native_theme = ui::NativeTheme::GetInstanceForWeb();
   SkColor theme_color = native_theme->GetSystemColor(
       ui::NativeTheme::kColorId_FocusedBorderColor);
@@ -133,6 +144,7 @@ SkColor AccessibilityFocusHighlight::GetHighlightColor() {
     return default_color_;
 
   return native_theme->FocusRingColorForBaseColor(theme_color);
+#endif
 }
 
 void AccessibilityFocusHighlight::CreateOrUpdateLayer(gfx::Rect node_bounds) {
@@ -193,6 +205,9 @@ void AccessibilityFocusHighlight::CreateOrUpdateLayer(gfx::Rect node_bounds) {
 }
 
 void AccessibilityFocusHighlight::RemoveLayer() {
+  if (no_fade_for_testing_)
+    return;
+
   layer_.reset();
   if (compositor_) {
     compositor_->RemoveAnimationObserver(this);
@@ -311,6 +326,29 @@ void AccessibilityFocusHighlight::OnPaintLayer(
   recorder.canvas()->DrawRoundRect(bounds, kBorderRadius, original_flags);
 }
 
+float AccessibilityFocusHighlight::ComputeOpacity(
+    base::TimeDelta time_since_layer_create,
+    base::TimeDelta time_since_focus_move) {
+  float opacity = 1.0f;
+
+  if (no_fade_for_testing_)
+    return opacity;
+
+  if (time_since_layer_create < fade_in_time_) {
+    // We're fading in.
+    opacity = time_since_layer_create / fade_in_time_;
+  }
+
+  if (time_since_focus_move > persist_time_) {
+    // Fading out.
+    base::TimeDelta time_since_began_fading =
+        time_since_focus_move - (fade_in_time_ + persist_time_);
+    opacity = 1.0f - (time_since_began_fading / fade_out_time_);
+  }
+
+  return base::ClampToRange(opacity, 0.0f, 1.0f);
+}
+
 void AccessibilityFocusHighlight::OnAnimationStep(base::TimeTicks timestamp) {
   if (!layer_)
     return;
@@ -338,21 +376,8 @@ void AccessibilityFocusHighlight::OnAnimationStep(base::TimeTicks timestamp) {
     return;
   }
 
-  // Compute the opacity based on the fade in and fade out times.
-  // TODO(aboxhall): figure out how to use cubic beziers
-  float opacity = 1.0f;
-  if (time_since_layer_create < fade_in_time_) {
-    // We're fading in.
-    opacity = time_since_layer_create / fade_in_time_;
-  } else if (time_since_focus_move > persist_time_) {
-    // Fading out.
-    base::TimeDelta time_since_began_fading =
-        time_since_focus_move - (fade_in_time_ + persist_time_);
-    opacity = 1.0f - (time_since_began_fading / fade_out_time_);
-  }
-
-  // Layer::SetOpacity will throw an error if we're not within 0...1.
-  opacity = base::ClampToRange(opacity, 0.0f, 1.0f);
+  float opacity =
+      ComputeOpacity(time_since_layer_create, time_since_focus_move);
   layer_->SetOpacity(opacity);
 }
 

chrome/browser/ui/views/accessibility/accessibility_focus_highlight.h

@@ -42,10 +42,13 @@ class AccessibilityFocusHighlight : public ui::LayerDelegate,
  private:
   FRIEND_TEST_ALL_PREFIXES(AccessibilityFocusHighlightBrowserTest,
                            DrawsHighlight);
+  FRIEND_TEST_ALL_PREFIXES(AccessibilityFocusHighlightBrowserTest,
+                           FocusAppearance);
   // For testing.
   static void SetNoFadeForTesting();
   static void SkipActivationCheckForTesting();
   static void UseDefaultColorForTesting();
+  ui::Layer* GetLayerForTesting();
 
   // Create the layer if needed, and set node_bounds_
   void CreateOrUpdateLayer(gfx::Rect node_bounds);
@@ -73,6 +76,11 @@ class AccessibilityFocusHighlight : public ui::LayerDelegate,
   // Compute the highlight color based on theme colors and defaults.
   SkColor GetHighlightColor();
 
+  // Compute the opacity based on the fade in and fade out times.
+  // TODO(aboxhall): figure out how to use cubic beziers
+  float ComputeOpacity(base::TimeDelta time_since_layer_create,
+                       base::TimeDelta time_since_focus_move);
+
   // The layer, if visible.
   std::unique_ptr<ui::Layer> layer_;
 
@@ -94,6 +102,9 @@ class AccessibilityFocusHighlight : public ui::LayerDelegate,
   // The default color used for the highlight.
   static SkColor default_color_;
 
+  // Whether to skip fade in/fade out for testing.
+  static bool no_fade_for_testing_;
+
   // The amount of time it should take for the highlight to fade in.
   static base::TimeDelta fade_in_time_;
 

chrome/browser/ui/views/accessibility/accessibility_focus_highlight_browsertest.cc

@@ -4,12 +4,18 @@
 
 #include "math.h"
 
+#include "base/path_service.h"
 #include "build/build_config.h"
+#include "cc/test/pixel_comparator.h"
+#include "cc/test/pixel_test_utils.h"
 #include "chrome/browser/ui/views/accessibility/accessibility_focus_highlight.h"
 #include "chrome/browser/ui/views/frame/browser_view.h"
+#include "chrome/common/chrome_paths.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/test/base/in_process_browser_test.h"
 #include "chrome/test/base/ui_test_utils.h"
+#include "components/viz/common/frame_sinks/copy_output_request.h"
+#include "components/viz/common/frame_sinks/copy_output_result.h"
 #include "content/public/browser/focused_node_details.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/notification_types.h"
@@ -20,6 +26,19 @@
 #include "ui/snapshot/snapshot.h"
 #include "ui/views/widget/widget.h"
 
+#if defined(OS_MAC)
+#include "base/mac/mac_util.h"
+#endif
+
+// To rebaseline this test on all platforms:
+// 1. Run a CQ+1 dry run.
+// 2. Click the failing bots for android, windows, mac, and linux.
+// 3. Find the failing interactive_ui_browsertests step.
+// 4. Click the "Deterministic failure" link for the failing test case.
+// 5. Copy the "Actual pixels" data url and paste into browser.
+// 6. Save the image into your chromium checkout in
+//    chrome/test/data/accessibility.
+
 class AccessibilityFocusHighlightBrowserTest : public InProcessBrowserTest {
  public:
   AccessibilityFocusHighlightBrowserTest() = default;
@@ -229,3 +248,98 @@ IN_PROC_BROWSER_TEST_F(AccessibilityFocusHighlightBrowserTest,
   // Not sure where the extra px of height are coming from...
   EXPECT_EQ(147, bounds.height());
 }
+
+class ReadbackHolder : public base::RefCountedThreadSafe<ReadbackHolder> {
+ public:
+  ReadbackHolder() : run_loop_(std::make_unique<base::RunLoop>()) {}
+
+  void OutputRequestCallback(std::unique_ptr<viz::CopyOutputResult> result) {
+    if (result->IsEmpty())
+      result_.reset();
+    else
+      result_ = std::make_unique<SkBitmap>(result->AsSkBitmap());
+    run_loop_->Quit();
+  }
+
+  void WaitForReadback() { run_loop_->Run(); }
+
+  const SkBitmap& result() const { return *result_; }
+
+ private:
+  friend class base::RefCountedThreadSafe<ReadbackHolder>;
+
+  virtual ~ReadbackHolder() = default;
+
+  std::unique_ptr<SkBitmap> result_;
+  std::unique_ptr<base::RunLoop> run_loop_;
+};
+
+const cc::ExactPixelComparator pixel_comparator(/*discard_alpha=*/false);
+
+IN_PROC_BROWSER_TEST_F(AccessibilityFocusHighlightBrowserTest,
+                       FocusAppearance) {
+  base::ScopedAllowBlockingForTesting allow_blocking;
+
+  AccessibilityFocusHighlight::SetNoFadeForTesting();
+  AccessibilityFocusHighlight::SkipActivationCheckForTesting();
+
+  browser()->profile()->GetPrefs()->SetBoolean(
+      prefs::kAccessibilityFocusHighlightEnabled, true);
+
+  ui_test_utils::NavigateToURL(browser(), GURL("data:text/html,"
+                                               "<a id='link' href=''>"
+                                               "<img width='10' height='10'>"
+                                               "</a>"));
+
+  FocusedNodeChangedObserver observer;
+
+  content::WebContents* web_contents =
+      browser()->tab_strip_model()->GetActiveWebContents();
+  std::string script("document.getElementById('link').focus();");
+  ASSERT_TRUE(content::ExecuteScript(web_contents, script));
+  observer.WaitForFocusChangeInPage();
+  BrowserView* browser_view = BrowserView::GetBrowserViewForBrowser(browser());
+  AccessibilityFocusHighlight* highlight =
+      browser_view->GetAccessibilityFocusHighlightForTesting();
+  ui::Layer* layer = highlight->GetLayerForTesting();
+
+  gfx::Rect source_rect = gfx::Rect(layer->size());
+  scoped_refptr<ReadbackHolder> holder(new ReadbackHolder);
+  std::unique_ptr<viz::CopyOutputRequest> request =
+      std::make_unique<viz::CopyOutputRequest>(
+          viz::CopyOutputRequest::ResultFormat::RGBA_BITMAP,
+          base::BindOnce(&ReadbackHolder::OutputRequestCallback, holder));
+  request->set_area(source_rect);
+  layer->RequestCopyOfOutput(std::move(request));
+  holder->WaitForReadback();
+  SkBitmap bitmap(holder->result());
+  ASSERT_FALSE(bitmap.drawsNothing());
+
+  base::FilePath dir_test_data;
+  ASSERT_TRUE(base::PathService::Get(chrome::DIR_TEST_DATA, &dir_test_data));
+
+  std::string screenshot_filename = "focus_highlight_appearance";
+  std::string platform_suffix;
+#if defined(OS_MAC)
+  // Mac 10.15 switched to a subtly different highlight color.
+  if (base::mac::IsAtMostOS10_14())
+    platform_suffix = "_mac10.14";
+  else
+    platform_suffix = "_mac";
+#elif defined(OS_WIN)
+  platform_suffix = "_win";
+#endif
+
+  base::FilePath golden_filepath =
+      dir_test_data.AppendASCII("accessibility")
+          .AppendASCII(screenshot_filename + ".png");
+  base::FilePath golden_filepath_platform =
+      golden_filepath.InsertBeforeExtensionASCII(platform_suffix);
+  if (base::PathExists(golden_filepath_platform)) {
+    golden_filepath = golden_filepath_platform;
+  }
+
+  bool snapshot_matches =
+      cc::MatchesPNGFile(bitmap, golden_filepath, pixel_comparator);
+  EXPECT_TRUE(snapshot_matches);
+}

chrome/browser/ui/views/frame/browser_view.h

@@ -593,6 +593,10 @@ class BrowserView : public BrowserWindow,
   // Create and open the tab search bubble.
   void CreateTabSearchBubble() override;
 
+  AccessibilityFocusHighlight* GetAccessibilityFocusHighlightForTesting() {
+    return accessibility_focus_highlight_.get();
+  }
+
  private:
   // Do not friend BrowserViewLayout. Use the BrowserViewLayoutDelegate
   // interface to keep these two classes decoupled and testable.